Vacuum control for fuel injection engines



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R. J. SCHROEDER 2,949,732

VACUUM CONTROL FOR FUEL INJECTION ENGINES Filed Sept. 0, 195'! Aug. 23, 1960 IN VE NT 0R:

4a ma QM ATTORNEYS.

Unite States Fatem Robert J. Schroeder, Wheeling, 111., assignor, by mesne assignments, to Allis-Chalmers Manufacturing Company, West Allis, Wis., a corporation of Delaware Filed Sept. 30, 1951, Ser. N5. 687,083

'3 Claims. on. 60-14) This invention relates to a vacuum control for fuel injection engines, and more particularly to a construction to provide a source of vacuum for operating brakes and similar accessories in vehicles powered by fuel injection engines, such as diesel engines.

In fuel injection engines it is customary to use an open air supply conduit and to control the engine by varying the amount of fuel supplied thereto. This means that the air supply conduit or manifold will remain at substantially atmospheric pressure at all times. Therefore, if vacuum operated accessories, such as brakes, are to be employed, it has been necessary to provide a separate vacuum pump driven by the engine.

It is one of the objects of the present invention to provide a vacuum control for fuel injection engines in which the air supply conduit for the engine is restricted to create a vacuum only during low speed or idling operation of the engine whereby the engine itself serves as a source of vacuum without interference with normal operation or efficiency thereof.

Another object is to provide a vacuum control in which a valve in the air supply conduit is closed by the usual accelerator pedal or other control member for a fuel pump when the control member is moved in a direction to reduce the fuel supply.

According to a feature of the invention, the valve is operated through a resilient link which is arranged to close the valve when the fuel supply is reduced to mini mum for idling, and which will yield as the control member moves in a direction to increase the fuel supply.

A further object is to provide a vacuum control in which a vacuum storage tank is provided connected to the air supply conduit posterior to the valve through a check valve opening toward the air supply conduit.

The above and other objects and features of the invention will be more readily apparent from the following description when read in connection with the accompanying drawing, in which:

Figure 1 is a side view with parts broken away of a vehicle embodying the present invention;

Figure 2 is a partial perspective view of the control linkage; and

Figure 3 is a section through a resilient link.

As illustrated in Figure 1, the invention is applied to a tractor or similar vehicle having a frame, indicated generally at 10, on which there is mounted a fuel injection engine 11, such as a diesel engine. The engine is provided with an air supply manifold 12, connected to an air supply conduit 13, having an atmospheric inlet opening leading through a filter 14, into the air supply conduit. The engine is also equipped with the usual exhaust manifold 15, and with a variable fuel pump 16. As is conventional, the pump 16 supplies fuel under pressure to nozzles discharging into the individual cylinders, and the quantity of fuel supplied is regulated through a control lever 17 on the fuel pump to vary the speed and power delivery of the engine.

The vehicle also includes an operators seat shown generally at 18, and a control member 19 in the form of a conventional accelerator pedal which can be easily operated by the foot of an operator seated in the seat 18.

The control member 19 controls the variable fuel pump 16, and for this purpose has an arm 21 extending below the pivot thereof, and a return spring 22 connected to the arm to urge the pedal 19 to its upper position, as shown in Figure 1, in which the fuel supply is at a minimum and the engine is idling. The arm 21 is connected through a link 23 to a crank arm 24, secured to a cross shaft 25, in the engine compartment of the vehicle. A second link 26, which may be a compressible link, connects the crank arm 24 to the control lever 17 of the variable fuel pump. When the pedal 19 is depressed, the links 23 and 26 will be shifted to the right to turn the control lever 17 clockwise, and increase the supply of fuel to the engine. When the pedal is released by removal of the operators foot therefrom, or by relaxing of the pressure thereon, the spring 22 will return the pedal to its elevated position and, through the links 23 and 26, will turn the control lever 17 toward the position shown to reduce the supply of fuel.

In order to create a vacuum in the air supply conduit 13 during low speed running and idling conditions of the engine, a valve 27 is provided in the air supply conduit. The valve as shown is of the usual butterfly type and may have an arm 28 secured thereto engageable with adjustable stops 29 on the air inlet conduit to limit the open and closed positions of the valve. Preferably, the valve is so constructed and the closing stop 29 is so adjusted that suificient air will leak past the valve when it is in its closed position to permit low speed and idling operation of the engine, even though the valve is closed.

To control the valve, the shaft 25 carries a second crank arm 31, which is connected through a compressible link 32 to the valve 27. The link 32 may be constructed, as best seen in Figure 3, of a pair of rods 33 and 34, and a sleeve 35, fitted over the ends of the rods. The rod 33 is rigidly secured in the sleeve, and the rod 34 is slidable therein, with its sliding movement limited by a pin 36 carried by the sleeve, and extending through an elongated slot 37 in the rod. A compression spring 38 in the sleeve engages the end of the rod 34 and urges it to the right, as shown in Figure 3, until the pin 36 seats on the left end of the slot 37. When compression is applied to the link, the rod 34 may move to the left against the spring 38 to limit the compressive force applied through the link.

The crank arm 31 is preferably longer than the crank arm 24, as shown, and is connected to the valve 27 at such an angle that the valve 27 will be closed at the same time the control lever 17 is moved to the minimum fuel supply position. Thus, at the time when the valve 27 is closed, and as the engine continues to operate, a partial vacuum will be created in the air supply conduit posterior to the valve, and may be utilized for the operation of accessories, such as vacuum brakes and the like.

In order to insure a constantly available supply of vacuum for the operation of such accessories, a vacuum storage tank 41 is provided connected through a conduit 42, to the air supply conduit 13, at a point posterior to the valve 27. A check valve 43 is included in the connection, preferably adjacent to the air supply conduit and opening toward the air supply conduit. The accessories to be operated by vacuum are connected through the usual control valves to the tank 41.

In operation of the system, when the engine is operating in its normal useful range the pedal 19 will be partially or fully depressed to move the pump control lever 17 partially or fully clockwise from the position shown, and the valve 27 will be open. Due to the construction of the linkage, it will be seen that the valve 27 will open i ully after only partial depression of the lever 19, and preferably when the lever is. depressed to approximately one-third throttle position. As the lever 19 is depressed further toward full throttle position the rod 34 will move to the left in the sleeve 35 compressing the spring 38. At full throttle the link 26 may be compressed'slightlyto insure full throttle opening without the possibility of bending or damaging any of the parts. Thus, in the normal operating ranges, the engine operates in the usual manner Without any interference from the vacuum control of the invention.

As the pedal 19 is elevated from the full throttle position, the lever 17 will be turned to reduce the fuel supply to the engine. However, during the first part of this movement, the valve 27 will remain fully open and the spring 38 will expand. When the lever 19 reaches approximately one-third throttle position the pin 36 will engage the end of slot 37 and during further upward movement of the lever the valve 27 and fuel control lever 17 will move simultaneously toward closing position. When the valve 27 is closed or very nearly closed, operation of the engine as it coasts down from high speed and continues to idle will create a partial vacuum in the air supply conduit posterior to the'valve.

Another advantageous feature of the invention is that it provides a safety feature in the event that the fuel control means sticks in open position so that the engine tends to run away. If this should occur on an engine equipped with the present invention the air valve 27 will close and the engine will receive insuflicient air to form with the relatively large quantity of fuel being supplied a readily combustible mixture. Therefore, the engine will either continue to run at low speed determined by the amount of air passing the valve, or will stop. In any event, the engine will not receive. a sufficient air supply with the valve closed to enable it to develop a dangerously high speed.

Under these conditions, air will. be withdrawn from the tank 41, past the check valve 43, to produce a partial vacuum in the tank which is available for operation of brakes or other accessories. When the valve 27 is again opened so that the pressure in the air supply conduit again approaches atmospheric, the check valve 43 will close so that the vacuum produced in the tank 41 will be maintained.

While one embodiment of the invention has been shown and described in detail, it will be understood that this is illustrative only and is not to be taken as a definition of the scope of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

1. A vacuum generating means on a fuel injection engine of the type having a variable fuel pump, a movable control member for the pump, and an air supply conduit means, said vacuum generating means comprising a valve in the air supply conduit, a vacuum tank, a vacuum connection between said tank and the air supply conduit downstream from the valve,j 'and linkage connecting the valve to the control member and including a yieldable link, the linkage being constructed and arranged to close the valve as the control member-is moved in a direction to reduce the fuel supplied'by the pump and to open the valve as the control member is moved in a direction to increase the fuel supply, the valve being fully opened by partial movement of the control member in said last named direction and the yieldable link yielding as the control member is moved further to increase the fuel supply to a maximum.

2. A vacuum generating means on a fuel injection engine of the type having a variable fuel pump, a movable control member for the pump, and an air supply conduit means, said generating means comprising a valve in the air supply conduit means, a vacuum connection to the air supply conduit downstream from the valve, a rocker shaft connected to the control member to be turned thereby, -a link connecting the rocker shaft to the fuel pump, and an elastic link connecting the rocker shaft to the valve, the links being so proportioned that when the control member is moved in a direction to increase the fuel supplied by the pump the valve will be fully opened before the fuel supply is increased to a maximum and the elasticlink will yield as the control member is moved further to increase the fuel supply to a maximum.

3. In combination with a fuel injection internal combustion engine of the type having an air supply conduit means and a variable fuel pump being controlled by a throttle linkage means including a movable member, a vacuum. generating means for operating auxiliary vacuum motor means, comprising: a valve in said air supply conduit means; a vacuum tank; passage means interconnecting said tank and said air supply conduit means downstream of said valve; a check valve in said passage means opening toward said conduit means; and other linkage means for controlling said valve, said other linkage means' including a yieldable link connected to said first mentioned linkage means for closing said valve when the movable member is moved to a position reducing the fuel supplied by the pump to a minimum and to adjust the valve to a full open position when fuel supplied by the pump is increased by partial movement of said movable member, after adjustment of said valve to a full open position said yieldable link yielding as the control member is moved further to increase the fuel supply to a maximum.

References Cited in the file of this patent UNITED STATES PATENTS 1,849,113 Porsche Mar. 15, 1932, 2,012,998 Junkers Sept. 3, 1935 2,470,382 Vanni May 17, 1949 2,721,629 Saussard Oct. 25, 1955 

